Vol. 16, No.1 (January 2017) – Preface
Understanding the Risk of LAS to the Environment
When researchers look at data in new ways, advances in science can frequently be made. However, when this new view ignores previous research on the subject, problems can arise. This volume of the CLER Review addresses the issue of Linear Alkylbenzene Sulfonate’s perceived environmental risk (based on a new look at existing data) versus what years of existing research tell us about the actual environmental risk. This volume also highlights the latest research into the fate, aquatic toxicity and environmental safety of LAS.
As an example of a new way of looking at existing data, Johnson et al. (2017) recently described an alternative approach to the ranking of the environmental risk of chemicals. Based on their approach, several chemicals (including LAS) were identified as having relatively high risks. The authors considered these chemicals to be neglected as there were no regulatory controls in place to address them.
The articles in this and all of the previous volumes of the CLER Review provide abundant evidence that LAS is certainly not a neglected chemical. It is, in fact, one of the most widely and thoroughly studied consumer chemicals in commerce today. In the first article in this volume, Heinze and McAvoy (2018) provide a commentary on the Johnson et al. (2017) article. The authors systematically review the points raised by the article and provide evidence to the weakness of the approach and conclusions. As Heinze and McAvoy indicate, LAS has been reviewed repeatedly and each review has come to the same conclusion – LAS is not a high risk chemical.
The second and following articles in this volume provide outstanding examples of the latest research on LAS. In the first article, Belanger et al. (2016) have improved the prediction of the aquatic toxicity of individual LAS carbon chain length homologs and commercial mixtures. After conducting new experimental studies on fish and aquatic invertebrates and using sensitive analytical techniques, the authors were able to develop updated acute Quantitative Structure Activity Relationships (QSARs) for LAS. Considering the robustness of the new data, improved normalization of toxicity data for commercial mixtures and an improved Species Sensitivity Distribution (SSD) were possible. As new data such as these are generated, confidence in the hazard assessment of LAS is increased.
In the next article, Menzies et al. (2017) used OECD 314A guideline studies to determine the rate and pathways of biodegradation for several surfactants. The test guideline is designed to replicate sewer conditions for a realistic simulation of the biodegradation potential for down the drain chemicals. The pathway observed for LAS in the study was consistent with what has been previously reported in literature – alkyl chain oxidation producing shortened sulfonated phenyl carboxylates followed by ring opening and desulfonation. Surprisingly, the experimental rate of biodegradation was not consistent with that observed in field studies (including the following article). The authors hypothesized this was a result of biofilms not being included in the method. The importance of biofilms for biodegradation was noted by Takada et al. (1994), who reported rapid removal of LAS by attached biofilms in an urban shallow stream.
In the final article, McDonough et al (2016) used advanced analytical methods to measure the concentrations of anionic surfactants in effluent samples from around the country. The mean measured LAS concentration (15.3 μg/L) was consistent with previously reported effluent levels and, once again, supports the fact that LAS is well removed during wastewater treatment. Additionally, the authors calculated the Predicted No Effect Concentrations (PNEC) for each surfactant and compared these to the measured effluent concentrations. The resulting values (toxic units (TU)) can be used to determine the environmental risk. Even under the worst case scenario of low flow receiving water conditions, the TU for LAS was calculated to be less than 1 and provides another confirmation that use of LAS is a low risk to the environment.
Despite an inaccurate perception of a high level of environmental risk of LAS by Johnson et al. (2017), the available evidence in this and previous volumes of the CLER Review overwhelming supports the environmental safety of LAS.
Ricky A. Stackhouse
Chairman, Council for LAB/LAS Environmental Research (CLER)
REFERENCES
Johnson, A.C., Donnachie, R.L., Sumpter, J.P., Jürgens, M.D., Moeckel, C., Pereira,M.G., 2017. An alternative approach to risk rank chemicals on the threat they pose to the aquatic environment. Sci. Total Environ. 599-600:1372-1381.
Takada, H. Mutoh, K., Tomita, N., Miyadzu, T. Ogura, N. 1994. Rapid removal of linear alkylbenzene sulfonate (LAS) by attached biofilm in an urban shallow stream.Water Res. 28:1953-1960; CLER Review 3:54-65, 1997.